Yuuko Yamada

Bio: Yuuko Yamada is an academic researcher from Wako Pure Chemical Industries, Ltd. The author has contributed to research in topics: Catalysis & Silyl ether. The author has an hindex of 1, co-authored 2 publications receiving 16 citations.

Development of Chelate Resin‐Supported Palladium Catalysts for Chemoselective Hydrogenation.

Abstract: Two kinds of palladium catalysts immobilized on a chelate resin bearing diiminoacetate or polyamine moieties on the polystyrene-divinylbenzene polymer were newly prepared by the adsorption of palladium (II) ions on these resins followed by the reduction to palladium (0) with hydrazine monohydrate. Both catalysts showed a similar activity for hydrogenation. A variety of reducible functionalities, except for benzylic alcohol, alkyl benzyl ether, silyl ether, and epoxide, could be reduced under the hydrogenation conditions using either catalyst. Since the palladium metal elution from the immobilized catalysts was never observed, the catalysts could be reused without any decrease in the catalyst activity for at least 5 runs.

Resin modified MIL-53 (Fe) MOF for improvement of photocatalytic performance

Abstract: Metal organic frameworks (MOFs) are fascinating materials for diverse applications due to their adjustability of aperture and structure Herein, a three-dimensional iron-based MOF with BDC linker (BDC = 1,4-benzenedicarboxylate), commonly known as MIL-53(Fe), has been synthesized and successfully composited with anionic resin (Amberlite IRA 200) and cationic resin (Amberlite IRA 900) resulting solid composite photocatalysts, AMIL-53 (Fe) and DMIL-53(Fe), respectively In the novel composite photocatalysts, bulky MIL-53(Fe) MOF solids are used as both a support to anchor the finely ground Amberlite IRA resin powders and as a visible light active component for the degradation of organic pollutants in water In addition to being a traditional support, the resins here were used as a co-catalyst (with loading ration of the resin to MIL-53(Fe) is controlled around 20 wt%) to capture and transfer pollutant molecule from bulk solution into the active centers of the composited catalysts Such an immobilization of the resins significantly alters MIL-53 (Fe) activity and degradation selectivity of dye pollutants; after 120 min of visible light illumination (λ ≥ 420 nm) removal yield of SRB (24%) by the bare MIL-53 (Fe) was apparently improved to 96% after MIL-53 (Fe) was modified by Amberlite IRA 900, DMIL-53(Fe) The tunable degradation order was demonstrated by employing AMIL-53 (Fe) for the selective degradation of cationic dyes while DMIL-53 (Fe) for the degradation of anionic dyes Furthermore, the composites activity was optimized by controlling resin to MOF ratio during immobilization Immobilization also improves ease of separation and recyclability of the original MOF Especially, AMIL-53 significantly reduces iron ion leaching resulting in an enhanced stability The photocatalytic mechanism under visible-light irradiation is also discussed

Recent Development of Palladium-Supported Catalysts for Chemoselective Hydrogenation

Abstract: This paper describes practical and selective hydrogenation methodologies using heterogeneous palladium catalysts. Chemoselectivity develops dependent on the catalyst activity based on the characteristic of the supports, derived from structural components, functional groups, and/or morphologies. We especially focus on our recent development of heterogeneous palladium catalysts supported on chelate resin, ceramic, and spherically shaped activated carbon. In addition, the application of flow technology for chemoselective hydrogenation using the palladium catalysts immobilized on molecular sieves 3A and boron nitride is outlined.

Development of a Unique Heterogeneous Palladium Catalyst for the Suzuki–Miyaura Reaction using (Hetero)aryl Chlorides and Chemoselective Hydrogenation

Abstract: A unique heterogeneous palladium catalyst (7% Pd/WA30) supported on an anion exchange resin, which contains N,N-dimethylaminoalkyl functionalities on the polymer backbone, was developed. 7% Pd/WA30 could smoothly catalyze Suzuki–Miyaura reaction of even less reactive heteroaryl chlorides and heteroaryl boronic acids to afford various (hetero)biaryls due to the electron-donating effect of the tert-amines on WA30 to Pd species. It was also applicable as a chemoselective hydrogenation catalyst, showing inactivity for the hydorogenolysis of tert-butyldimethylsilyl (TBS) ethers, alkyl benzyl ethers, and benzyl alcohols. The tert-amines on WA30 acted as moderate catalyst poisons for Pd, resulting in chemoselective hydrogenation. 7% Pd/WA30 was reused for at least five times without any loss of the hydrogenation catalytic activity.